A wide variety of apparatus has previously been developed for various aspects of floor treatment, including, for example, finishing, buffing and stripping floor surfaces, as well as carpet cleaning. Floor treating machines typically comprise a treatment surface such as a polishing or stripping pad or brush, connected to a rotary drive means. It has long been known that orbital motion for the treatment surface can be especially effective for polishing or stripping. Such orbital motion is typically imparted by using a drive assembly in which force from the rotary drive means is transmitted through a bearing assembly or flywheel that is eccentrically mounted on a drive shaft linking the drive means to the treatment surface. Typical of such devices is that shown in Oreck et al., U.S. Pat. No. 5,355,542, hereby incorporated by reference. A disadvantage of orbital motion in such apparatus is vibration resulting from the eccentric mounting of the assembly. In the past, this been partly alleviated by counterbalancing of the flywheel. However, vibration remains a problem, and continuing effort has been directed to the improvement of such apparatus.